Available in all subroutines.
In order for the ESI parser to detect
<esi:... tags in the response stream, the response cannot be compressed. Compressed responses will obfuscate the ESI tags and they will be delivered unprocessed to the client.
Try it out
esi is used in the following code examples. Examples apply VCL to real-world use cases and can be deployed as they are, or adapted for your own service. See the full list of code examples for more inspiration.
Click RUN on a sample below to provision a Fastly service, execute the code on Fastly, and see how the function behaves.
Relative date insertion using ESI
Edge-side includes (ESI)
Use Fastly's support for ESI to combine multiple origin-hosted objects into a single response at the edge.